US Defence Secretary James Mattis (L) and Joint Chiefs Chairman Marine Gen. Joseph Dunford leave after a press briefing on the campaign to defeat Daesh at the Pentagon in Washington, US, May 19, 2017.

US Secretary of Defence James Mattis says the fight against Daesh is accelerating and the US-led coalition plans to circle Daesh fighters in their Syrian strongholds, before launching a campaign to destroy them.

The coalition also appears to be targeting Assad loyalists. On Thursday, American warplanes hit pro-regime forces in order to protect British and American soldiers in the country's southeast.

Turkish Concerns

US Diplomat Brett McGurk, who is the US envoy in the battle against Daesh, says Turkey remains a crucial ally in the fight against the terror group.

He made the comments a day after the Turkish Foreign Minister Mevlut Cavusoglu demanded McGurk be sacked.

Cavusoglu accused him of supporting the YPG and the outlawed PKK. Relations between the NATO allies have been strained over the US backing of YPG in Syria.